OBJECTIVES: a. Overall objective: (1) To determine the nature of the interaction between human alveolar macrophages (AM) and microorganisms, i.e., whether viruses, bacteria and fungi are killed by AM or conversely, whether they can grow and replicate within AM. (2) To compare this AM-macrophage interaction in normal versus immunosuppressed patients. b) Goals for current year: (1) Develop methodology for infecting AM with herpes simplex virus (HSV) and assaying viral replication within these cells. (2) Apply existing methods to determine whether AM permit replication or kill representative bacteria and fungi. (3) Compare (1) and (2) in normals versus patients with such diseases as occult hemorrhage, alveolar proteinosis, leukemia and Hodgkins disease. BIBLIOGRAPHIC REFERENCES: Golde, D.W., W.L. Drew, H.Z. Klein, T.N. Finley, and M.J. Cline: Occult pulmonary haemorrhage in leukaemia. Brit Med J, 2:166-168, April 26, 1975.